(Not Applicable)
(Not Applicable)
The present invention relates in general to drying tools for drying moisture present within cells of honeycomb cores, and in particular to a drying tool with an inflatable bladder compartment from which a plurality of open-ended nozzles protrude and through which upstream hot air supplied to the bladder compartment is pinpointedly directed against the honeycomb core at a plurality of sites for forcing a circulation of hot air among the cells to thereby remove moisture content.
Honeycomb cores are commonly employed in the construction of many structures that require relatively light weight coupled with relatively strong integrity. Chief among examples of such structural requirements is that of components of an aircraft. In particular, floor panels, engine nacelles, flaps, leading edge components, overhead bins, galley cabinetry, and the like all can be fabricated using a honeycomb core sandwiched between adhesively attached external skin material such that an integrated strong construction is achieved while overall aircraft weight objectives are maintained. One such honeycomb core product that is widely utilized is fabricated from NOMEX aramid paper (NOMEX is a registered trademark of the DuPont Company, Wilmington, Del.), and exhibits flame and chemical resistence as well as good thermal insulation.
While initial fabrication of such honeycomb core products is relatively straightforward, the repair of a damaged product whose skin, typically a composite material, requires replacement, can be a difficult task. Specifically, two major factors contribute toward skin replacement success. First, because the replaced composite skin is applied before being cured and therefore is cured in place, a curing temperature at least above 200xc2x0 F. must be applied to cure the composite material, and this temperature also heats the adjoining honeycomb core. Second, because of ambient exposure of the honeycomb core water moisture enters the honeycomb cells, and this trapped moisture can expand up to 1,200 times normal when the core is heated above the boiling point of water. When this expansion occurs, the cellular structure of the honeycomb core is damaged and disbanding of the replacement skin occurs.
As is thus apparent, proper repair of such a structure with a honeycomb core is greatly enhanced in relation to successful drying of the core structure. At present, such moisture removal is typically attempted by using heat blankets and/or blown hot air on top of the core to theoretically cause wicking of moisture upwardly within the core and thereby promote core drying. Unfortunately, however, this existing approach is generally inefficient since pockets of air inherently present in the core cells themselves resist circulation of applied heat and thus resist moisture wicking and drying. Consequently, a need is present for a drying tool capable of eliminating moisture present in honeycomb core cells and thus promote proper repair results for exterior skin patching. In accord therewith, a primary object of the present invention is to provide a drying tool capable of delivering hot air to moisture sites within a honeycomb core.
Another object of the present invention is to provide a drying tool constructed to simultaneously direct a multitude of hot-air streams precisely in line with core cells for forcing heat circulation and moisture desiccation.
Still another object of the present invention is to provide a drying tool whose directed hot-air streams are flexibly positional against a honeycomb core for intimate-interface contact with the shaped surface of the core.
These and other objects of the present invention will become apparent throughout the description thereof which now follows.
The present invention is a drying tool for drying moisture present in cells of a honeycomb core. The tool includes an inflatable bladder compartment having a bendable generally flat exterior surface and a plurality of open-ended nozzles protruding from this exterior surface, with each nozzle having a passage there through in fluid communication with the bladder compartment. Finally, a connector element is provided to be in fluid communication with the bladder compartment and connectible with a hot air source for delivering hot air into the bladder compartment for subsequent dispatch therefrom through the plurality of nozzles. Preferably, the nozzles are situated in a grid formation and are of a generally conical configuration. In use, the bendable exterior surface with the protruding nozzles is bowed or curved to generally configure to the exterior shape of the honeycomb core such that hot air is pinpointed in a grid pattern to drive heated air into the core and thereby cause circulation through the core cells for moisture evaporation. In this manner, a non-curedcomposite repair patch can be applied and adhered over and to the exposed honeycomb core portion and thereafter cured in place at a required cure temperature without fear of core damage due to moisture expansion and resulting disbanding of the patch.